Theauthorsprefertousea3–5×2–4cmdiamond-shapedislandflap comprisingfullthicknessskinandsubcutaneousfat.Theflapoutlineis firstmarkedonthenonscarredbuttockskin(Figs.6-9and6-10AandB). Theflapiselevatedusingdiathermy,aimingtoensurethattheedges slopeoutlaterallyinthesubcutaneoustissuetogiveabroaderbase;this actionreducestheriskoftheflapbeingdevascularized,whenitis advancedintotheanalcanal.

externalcomponentofthetract,extendingfromtheexternalopeningto theexternalsphincter,isalsoexcised.Thescartissuebetweenthe internalandtheexternalopeningsisalsoroutinelyincised,andif feasible,excised;or,alternatively,curetted.

Itisveryimportanttodisconnecttheleadingedgeoftheflapfromthe subcutaneoustissuesattachedtothesphinctertogivemobility.Oncethe flapismobile,itisadvancedintotheanalcanal(Figs.6-11AandB)and usedtocovertheinternalopening.Itisusuallynecessarytorotatethe flapfromthecontralateralsidetocoveramidlinedefectbecauseof ipsilateralscarring.Theflapissuturedinsituusinginterrupted2/0–3/0 absorbablebraidedsutures(polyglactin)(Fig.6-12AandB).Thebuttock defect,outsidetheadvancedflap,isalsoclosedusing2/0braided absorbablesuturesinalinearfashion.Braidedabsorbablesuturesare usedforpatients’comfort.

Asmalldrain,suchasasmalldePezzerormushroomtipcatheter,is placedintolargertractsviatheexternalopening.

Note:OthersprefertouseabroadbasedU-shapedinverted

anocutaneousflap.Theapexoftheflapshouldbe2–2.5cminwidthand sitedjustproximaltotheinternalopening.Itismarkedoutsothatthe baseisapproximatelytwicethewidthoftheapex.Thebasecanbe releasedfrom(asahouseflap)orleftattachedtothebuttockasa “tongue.”Proximally,theflapshouldencompassthesuperficialfibersof thelowerinternalsphincter.Thelengthshouldbesuchthatitallowsa tension-freeclosure.Thedistalpartoftheflapwillincludetheskinand subcutaneousfatoftheperianalregion.Furtheradvancementcanbe gained,ifrequired,byexcisingBurrow’strianglesofskinfromthe adjacentbase.Adisadvantageoftheseflapsisthattheyhavelimited lengthofmobilitywhencomparedwiththeislandflapsthatcanbe mobilizedabovetheanorectaljunctionwhenneeded,forexample, followingafailedrectaladvancementflapforarecurrent suprasphinctericfistula.

28.4(range4–63)months.

Despitefamiliaritywithtechniqueandexpertise,allcolorectalsurgeons areawareofthechallengescomplexfistuladiseaseposeandthe frustrationoffailureandrecurrence.Nottheleast,otherwisehealthy youngpatientswithcomplexfistulaefindthediseasefrustratingand oftendifficulttocomprehendintermsoftheneedforstagedrepairsand potentialneedformultipleprocedures.Goodresultsaredependentonan understandingoftheanatomyofthepathologicalcondition,controlof sepsispriortoaflaprepair,andattentiontodetailtoensureatension­free,well-vascularizedflap.

TheauthorswouldliketothankProfessorA.Eyersforhiskind permissiontousehisEndorectalAdvancementFlapvideointhis publication.